西红花FT同源基因的表达及功能分析

FT（FLOWERING LOCUS T）及其同源基因作为三大开花途径整合子之一，被认为是调控植物开花的重要基因。为了深入研究FT同源基因的功能以及西红花（Crocus sativus L.）开花的分子机理，对已报道的3个西红花FT同源基因（CsatFT1、CsatFT2和CsatFT3）进行分离及分析。gDNA包含长度分别为835、1 642和1 132 bp的完整开放阅读框（ORF），均具有4个外显子和3个内含子；cDNA包含长度分别为528、525和540 bp的ORF，分别编码175、174和179个氨基酸；系统进化分析表明，CsatFT1、CsatFT2、CsatFT3分别和同为单子叶植物的水仙（Narcissus chinensis）NtFT、麝香百合（Lilium longiflorum）LlFT和洋葱（Allium cepa）AcFT1表现出较近的遗传距离。qRT-PCR分析结果显示，小球茎膨大阶段前期，CsatFT1、CsatFT2、CsatFT3在叶片中表达水平最高，侧根中次之，子球茎、主根中极低几乎检测不到；小球茎膨大阶段后期，CsatFT1、CsatFT2、CsatFT3都在子球茎中表达水平较高，在顶芽中几乎检测不到；室内储藏开花阶段，CsatFT1、CsatFT2、CsatFT3在柱头中表达水平最高，叶中次之，花瓣和花药中较低几乎检测不到。通过观测转基因烟草（Nicotiana tabacum）和转基因拟南芥（Arabidopsis thaliana）植株表型发现，CsatFT1，CsatFT2和CsatFT3均具有促进植物提早开花的功能。

Expression and Functional Analysis of FT Homologous Genes in Saffron(Crocus sativus L.)

As one of the three floral pathway integrators,FT(FLOWERING LOCUS T)and its homologous genes were considered to be important genes which related to flowering.In order to clarify the function of FT homologous genes and flowering mechanism of saffron(Crocus sativus L.),the three reported FT homologous genes,named CsatFT1,CsatFT2 and CsatFT3,were isolated and analyzed.The gDNA contained the ORF with length of 835,1642 and 1132 bp,respectively,and they all had 4 exons and 3 introns.cDNA sequences contained the length of 528,525 and 540 bp ORF,which encoded 175,174 and 179 amino acids,respectively.The phylogenetic analysis indicated that CsatFT1,CsatFT2 and CsatFT3 showed relatively close genetic distance with the monocotyledon Narcissus tazetta NtFT,Lilium longiflorum LlFT and Allium cepa AcFT1,respectively.qRT-PCR results indicated that the expression levels of CsatFT1,CsatFT2 and CsatFT3 were the highest in the leaves,followed by the lateral roots,and almost no expressed in daughter corms and primary roots at the early stage of replacement corm enlargement.At the late stage of replacement corm enlargement,the expression levels of CsatFT1,CsatFT2 and CsatFT3 were all high in daughter corms and were almost not detected in terminal buds.During indoor storage stage,the expression levels of CsatFT1,CsatFT2 and CsatFT3 were high in the capital,followed by the leaves,and almost undetectable in the petals and anthers.From the phenotypes of transgenic tobacco and transgenic Arabidopsis plants,the results showed that CsatFT1,CsatFT2 and CsatFT3 could promote the early flowering of plants.